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Analysis of summer heat budget of lakes under a changing climate across a geographic gradient

Number of pages36
PublisherUniversité d'Uppsala/UNIGE
First online date2023-05-10
Abstract

Warming surface water temperature is the most direct consequence of climate change in lakes and therefore, predicting the heat exchange at the air-water interface is important to understand how atmos-pheric forcing will affect lake temperature and thermal structure. Here, we forced a one-dimensional hydrodynamic lake model with outputs from four different climate models under three future green-house gas emission scenarios from 1976 to 2099. To investigate the changes in summer (June to August or December to February in the northern or southern hemisphere, respectively) net surface heat flux and the individual flux components for 47 lakes with varying in size and geographic location were analysed. The results show that in the most extreme case (RCP 8.5) summer lake surface temperature is projected to increase by 4.72±0.70 °C by the end of the 21st century, due to increasing absorption of solar radiation (17.40±8.81 W m-2) and of long-wave radiation (33.01±5.44 W m-2). The increased lake surface tem-perature, also lead to higher heat losses to the atmosphere by outgoing long-wave radiation (27.54±4.07 W m-2) and by latent heat flux (25.10±7.37 W m-2), while a lower heat loss by sensible heat flux is projected (-3.20±1.94 W m-2). Altogether, the net heat balance and thus the accumulation of heat in the lakes over summer remains almost unchanged. However, a shift in the contributions of the individuals heat fluxes is projected, with the latent heat flux gaining relative importance.

Keywords
  • Modelling
  • Climate change
  • ISIMIP2b
  • Simstrat
  • Total surface heat flux
  • Surface heat flux components
  • Outgoing long-wave radiation
  • Sensible heat flux
  • Latent heat flux
Research groups
Citation (ISO format)
AYALA ZAMORA, Ana Isabel et al. Analysis of summer heat budget of lakes under a changing climate across a geographic gradient. 2023
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accessLevelPublic
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  • PID : unige:168713
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Creation10/05/2023 13:32:41
First validation15/05/2023 09:59:27
Update time15/05/2023 09:59:27
Status update15/05/2023 09:59:27
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